Dyestuff composition



UNITED STATES I PATENT OFFICE Earl W. Clark, Buflalo, N. Y., assignor to Allied Chemical & Dye Corporation, New York, N. Y., a corporation of New York a No Drawing. Application August-13, 1943,

u Serial No. 498,575 l This invention'relates to dyestuff compositions,

. and particularly to improved dyestuff compositions containing a salt of an acid polybasic acid ester, especially an acid sulfuric acid ester, of a leuco compoimd of a vattdyestufi, or a mixture of such salts and'to a process for coloring textile materials therewith." s

Salts of acid polybasic acid esters of leuco compounds of vat' dyestuffs'of various classes (e.g.. indigoicl, thioindigoid, anthraquinonee'tc.) are well known in the art. Usually they appearionthe market in the form of'sodium salts'of acid sulfuric acid esters'of leuco compoundsof vat dyestuffs; but salts of other metals, especially alkali metals, and of ammonia and organic bases, and of acid esters of other polybasic acids (such as, phosphoric acid andmaleicacid), are also known. For simplicity, they will be referred to hereinafter by the term vat dyestuif ester salts,

and those derived from sulfuric acid will be referred to by the term vat dyestufi sulfuric ester sa ts.

The aforesaid ester salts are stable forms'of leuco compounds of the vat dyestuffs from which they are derived. They are not reoxidized to the parent vat dyestufi upon exposure to air; they are relatively more soluble in water thanthe parent compounds, and form neutral aqueous solutions; and they are, generally substantive toward animal fibers (e. a, wool, silk, nylon, casein wool). Their aii'inity for vegetable fibers is in general poor, although this afiinity can be improved by the addition of an exhausting agent, 0. g;,"Glaubers salt, and/or raising the temperature at which the fiber is impregnated with the ester salt. When subjected to mild oxidizing agents (such as nitrites, chromates, etc.) in dilute acid solution, a vat'dyestuff ester salt of the aforesaid type is converted into the corresponding parent insoluble vat d'yestuff. Accordingly, the use of these ester salts in" coloring textile materials requires neither the strongly'alkaline conditions nor the complicated compounding and control required for dyeing and printing with the ordinary vatdyestuffs. I

For example, cotton, wool, silk, or rayon material can be colored by working it in a dye bath or padding hath consisting of an aqueous solution made by dissolving a vat dyestufi sulfuric ester salt in water, followed by treatment with an acid oxidizing solution (such as a dilute aque ous solution of sulfuric acid containing sodium dichromate'dissolved therein; or the material can be printed or'padded with a paste containing the '14 Claims. (ore-70) witherwithoutaclditional substances (such as sodiumnitrite; sodium chromate,-alcohols, glycerine, glycols, polyglycols, phenols, dioxydiphenyl sulfide, etc.), followed by an acid steaming treatment (so-called acid ageing) ortreatment with anacid oxidizing solution or both (of. U. S. P.

1,575,958) Insome casesthe printing or paddin'gpaste contains substances which form an acid oxidizing medium during the steaming operation (such as, sodium chlorate, ammonium sulfocyanide and ammonium vanadate) thereby makingunnecessary an acid oxidizing treatment. In generalthe dyed or printed material is further treated in a manner similar to that employed in coloring with vat dyestuffs; e. g., it is rinsed, soaped and finished. 1

The vat dyestuff ester salts of a number of V vat dyestuffs of the indigo, thioindigo, and an-" thraquinone series have been found suitable for commercialfapplication in coloring textile materialsin the'a-foresaid manner. j However, it has beenjfound that printing pastes containing'the said ester salts are generally unstable, their dye strength'decreasing considerably on standingfcr appreciable periods of time. I In commercial op erations, where uniformity of printing is highly desirable, this characteristic render the preparation of a large quantity ofa printing paste for.

use over a considerable period of time imprac tical and wasteful. Moreover, ester salts of a number of vat dyestuffs are unsuitable for printing because of their poor solubility in aqueous media. I

In accordance with the present invention, improved coloring compositions, containing salts of acid polybasic acid esters, and especially acid sulfuric acid esters, of leuco compounds of vat dyestuffs as coloring constituents, are obtained by incorporating into such coloring compositions a xanthinic' base (for example, theobromine, caffeine). As employed herein, and in the ap-' pended claims, the expression xanthinic base refers to a xanthine base of truly'basic character, 1. e., yielding a solution in water having a pH value of more than 7.0.

not subject to the aforesaid disadvantages, andthat the presence of the xanthinic base in the said composition imparts various advantages to it. Thus I have found the incorporation of caffeine into a printing paste containing a vat dyestufi' sulfuric ester salt imparts improved fixa tion properties to the ester salt, and results in vat dyestufl sulfuricv ester salt and a thickener, prints which have greater tinctorial strength and tion of caiieine to a printing paste'of a vat dye stuff sulfuric. ester salt improves the stability of the paste against decomposition of the ester salt upon standing, thereby permitting preparation" of large uniform batches of the printing paste which may be kept withoutexcessive loss of dye strength for longer periods of time thansimilar pastes which do not contain a xanthinic base.

I have also found that the xanthinic bases have a solubilizing effect upon relatively insoluble vat dyestuif sulfuric ester salts; that is, those having a solubility in water at 25 C. not exceeding is 544 grams.)

greater amount of the xanthinic base may be required. In general, the amount of xanthinic base should be at least one-quarter of the weight of the vat dyestuif equivalent of the salt of the acid sulfuric ester of the leucc compound of the vat dyestuff, and in some cases it maybe 5 or more times the wei ht of the vat dyestuff equivalent of said salt. (The term vat dyestufi equivalent, as employed herein, refers to the weight of unreduced vat dyestuff which is theoretically required to produce the given weight of vat dyestuif sulfuric ester salt. Thus, the vat dyestufi equivalent of 750 grams of the disodium salt of theacid sulfuric acid ester of the leuco compound of the blue-green vat dyestuff referred to above A greater amount of xanthinic vvbase may be used; the excess acts as a diluent.

by weight. It is well known that the solubility in aqueous media of salts of acid sulfuric acid esters of leuco compounds of vat dyestuffs varies' considerably with the nature of the parent vat dyestuff as well as with the nature of the cation whicli salt has such a low solubility in water that it cannot be used commercially for printing textile fibers, the resulting composition has sufficient solubility in water and printing pastes to be useful in producing commercially acceptable prints in the ordinaryprinting processes.

Any member of the class of xanthinic bases may be employed according to thi invention, for example, xanthine itself, l-methyl xanthine, heteroxanthine (7-methyl xanthine), theophylline (1,3-dimethyl xanthine), paraxanthine (1,7-v dimethyl xanthine'), theobromine (3,7-dim'ethyl xanthine), 1'hydroxyethyltheobromine (l-hydr0Xyethyl-3,7-dimethyl xanthine), cafieine (1,3,7-trimethyl xanthine), and epiguanine (7- methylguanine). Those which are methyl derivatives of xanthine are preferably employed, and especially caffeine. Crude caffeine, such as is obtained as a result of the decaffeination of coffee, tea and the like, preferably after only a single recrystallization, and which is in a form comprising more than 90% by weight of caffeine in admixture with other xanthinic bases and/or other substances naturally occurring in coffee,

tea and the like, is especially preferred in view of its relative cheapness and high eiTectiveness.

It will be understood that, in speaking of caffeine in the specification and claims, the pure as well as the crude form is intended, unless otherwise indicated.

The amount of Xanthinic base employed in accordance with the present invention may be Varied considerably. In general, the optimum amount employed in a particular case will depend upon a number of factors, including the solubility of the vat dyestuff ester salt, the specific xanthinic base used, and the manner in which the vat dyestuff ester salt is to be employed. Thus, in the case of a vat dyestuff sulfuric ester salt which is relatively soluble in water and printing pastes, only suificient xanthinic base need be included in a printin paste to produce improved prints or to impart desired stability to the print ing paste. On the other hand, if the xanthinic base is employed for the purpose of imparting increased solubility in aqueous media to a relatively insoluble vat dyestuff sulfuric ester salt, a

I The addition of the xanthinic base to the compositions of the present invention can be made in any suitable manner and at any desired stage of the preparation of the final composition. Thus, an improveddyestud composition can be produced'by mixing the xanthinic base with the vat dyestuff ester salt in the dry form, for example, by mixing" orgrinding them together; or, in the preparation of a dye bath or padding bath or printing paste, the xanthinic base may be added before or afteror together with the vat dyestufi? ester salt. Dry compositions also can be prepared by adding the xanthinic base to a solution of the vat dyestuff ester salt and evaporatmg the solution to dryness.

The xanthinic bases do not interfere with the inclusion in the compositions of other substances ordinarily forming a part of 'vat dyestuif ester salt compositions. Thus, in preparing dyestuff pastes, printing pastes, or powders of the vat dyestuif ester salts in accordance with the present invention, the xanthinic base may be used to replace a part of the water, diluent, or standardizing agent normally employed, if desired without otherwise changing the nature and proportions of the components of the pastes or powders. For example, additional substances having diluent,

- antifoaming, assisting, wetting, hygroscopic, catalytic, enolizing, or other desired action in the subsequent use of the compositions may be included in the compositions of the present invention. As indicative of the type of substances referred to, a number of which are known in the art, there may be mentioned inorganic salts (such as'sodium carbonate, sodium sulfate, etc.) which serve 'as diluents or alkalinizing agents; solvents (such as alcohols, etc.) hygroscopic liquids (such as glycerine, glycol, diethylene glycol, etc.) organic salts (such as sodium naphthionate, which serves as a printing assistant, etc); and organic fillers (such as dextrine, cerelose, etc). In the preparation of printing pastes and related compositions, conventional thickeners are also included (such as gum tragacanth, locust bean gum, starch, dextrine, etc.).

The invention will be further described in connection with the following illustrative examples, wherein parts and percentages are by weight and temperatures are in degrees centigrade.

EXAMPLE 1 A powder for use in textile printing, containing caffeine and the disodium salt of the acid sulfuric acid ester of the leuco compound of National Carbanthrene Blue Green FFB (Colour Index No. 1173), a blue-green vat dyestuff obtainable by thionation of 2-methyl-benzanthrone, is prepared by adding a wet filter-cake containing 233 parts of the said disodium sulfuric ester salt (equivalentto 169 parts of the corre'spondingyat dyestuff: National Carbanthrene Blue Green FFB) to an aqueous caffeine solution-which has been prepared by dissolving 9.6 parts .of' sodium hydroxide, 250 parts of caffeine,57.5 parts of sodium carbonate and 360 parts of soluble dextrinein the mixture (equivalent to a concentration of the corresponding vat dyestufi of about 15.5%

of the total solids in the mixture). The liquid mass is dried, for exampleon a drum drier, and the product is ground to the'desired degree of fineness. z T

EXAMPLE 2 Two similar printing pastes are prepared from the following'dyestuff.composition in the following manner:

' Solution A n One part of a dyestuff composition containing, per hundred parts,

, 7 Parts The disodium salt of the acid sulfuric acid ester of the leuco compound of National Carbanthrene Blue Green FFB (equiva-' lent to parts of National Carbanthrene Blue Green FEB) 27.6 Sodium hydroxide 0.96 Sodium carbonate 5.75 Soluble dextrin 65.69

is mixed with 2.5 parts of denatured alcohol (U. S. Formula 2B) and 1 part of crude caffeine is added, followed by 5.5 partsofhot water (at 80) and 2 parts of diethyleneglycoli Solution B Cne part of the same dyestuff composition is mixed with 6.5 parts of the denatured alcohol, to which mixture is added 5.5 parts of hot water (at 80) and 2 parts of diethylene glycol.

Each of the resulting solutions is mixed with 48 parts of a starch-tragacanth thickening (con taining 6.2% of wheat starch, 2.9% of gum tragacanth, 1.44% of sodium benzoate, and 89.46% of Water) and 4 parts of a neutral sodium chromate solution (prepared by dissolving 48 parts of sodium chromate: NazCrOiAHzO in 100 parts of Water) are added to the resulting paste.

Cotton cloth is printed with a portion of each ofthe printing pastes as thus prepared. After drying, the printed cloth is subjectedto an acid aging process by exposing it for about 3 minutes to the action of steam containing acetic and/or formic acid vapor (for instance, the vapor obtained by boiling a aqueous solution of acetic acid). If the coloration is not fully developed,

development can be completed by passing'the material through an aqueous Solution containing about 3.8% sulfuric acidand 5.0 grams of sodium bichromate (Na2CI'2O'L2I-I2O) per liter. When the development is complete, the material is rinsed, soaped and finished in the usual manner.

The printing paste prepared from Solution A (containing caffeine) yields a blue-green print similar in shade to that obtained by employing the parent vat dyestuff. The print is stronger, greener, brighter and more level than that produced in the same manner with the printing 6; paste preparedfifrom: Solution B (containing no caffeine).

Another portion of each of the printing pastes is. permitted to stand for 3 days and then is employed for printing cotton cloth'in the aforesaid manner. Very much stronger prints are obtained with the paste prepared from Solution A (containing caffeine) than with the paste'prepared from Solution B (containing no caffeine).

EXAMPLE 3 I I S/ \S/V is prepared by. intimately mixing in the dry form (e. g., by grinding together) 60 parts of a drydyestuff composition containing 65.6 parts of the disodium'salt of the acid sulfuric acid ester of the leuco compound of the aforesaid naphthioindigo (equivalent to 43.2 parts of the parent naphthioindigo) and 14.4 parts of water-soluble inorganic salts (associated with the ester salt, partly formed during the preparation thereof, and consisting essentially of sodium carbonate, trisodium phosphate, sodium sulfate and sodium chloride), with 15 parts of crude caffeine and 5 parts of 1,4-sodium naphthionate (containing about 10% of sodium sulfate). When used for preparing a printing paste which is printed on cotton, prints are obtained which are very much stronger than similar prints obtained in the absence of the caffeine.

EXAMPLE 4 Two similar printing pastes are prepared from the following dyestuff composition in the fol1owing manner:

Solution Parts A dyestuff composition containing, per 109 parts of composition"; The disodium salt of the acid sulfuric acid ester of the leuco compound of the naphthioindigo of Example 3 (equivalent to 54 part of the parent naphthioindigo) 8 .1

Water-soluble inorganic salts 1 .9

are mixed with 2.5 parts of denatured alcohol (218), and 0.3 part of crude caffeine and 0.1 part of 1,4-sodium naphthionate (containing about ofsodium sulfate) are added, followed by 15.5 parts of hot Water (at and 2 parts of diethylene glycol.

dbl)

Solution D drying, the printed cloth is subjected to acid aging for about 3 minutes in the vapor obtained by boiling a 25% aqueous solution of acetic acid. To complete color development, the material is passed through an aqueous solution of sulfuric acid and chromate of the type referred to above. The material is rinsed, soaped and finished in the usual manner.

The printing paste prepared from Solution C (containing caffeine) yields a brown print similar in shade to that. obtained by employing the parent vat dyestuff. The print is stronger and more level than that produced in the same manher with the printirn paste prepared from Solution D (containing nocaffeine).

Another portion ofeach of the printing pastes i permitted to stand for '7 days and then is employed for printing cotton cloth as above described. lhe prints obtained with the paste ob tained from Solution C (containing caffeine) showed the same superiority to the prints ob tained with the paste prepared from Solution D (containing no caffeine) as the freshly prepared paste.

It will be realized by those skilled in the art that the invention is not limited to the foregoing examples and that changes can be made without departing from the scope of the invention.

Thus, instead of the salts of the acid sulfuric acid esters of the leuco compound employed in the foregoing examples, salts of acid sulfuric acid esters of other vat dyestuffs may be employed; as for example, the sodium salts of the acid sulfuric acid esters of the leuco compounds of the following vat dyestuffs:

4,4'-dimethyl-6,6-dibrom thioindigo, 5,5 -dichl-or-6,5-dirnethy1 thioindigo, 6,6-diethoxy-thioindigo,.or 3, l,8,9-dibenzopyrene-5,10--quinone.

Similarly other salts of the above or other acid sulfuric acid esters of leuco compounds of other vat dyestuffs of the anthraquinone, indigoid and thioindigoid series may be employed in accordance with the present invention.

In the foregoing description. the use of the compositions in the dyeing or printing of textile materials has been stressed, since these are the more important applications of the compositions. It will be understood, however, that the compositions also may be used in the coloring of other substances wherein vat dyestuif sulfuric ester salts are applicable. It will also be understood, that this invention can be applied to dyestuff compositions comprising salts of leuco esters of vat dyestuffs derived from other polybasic acids, both inorganic and organic, e. g., phosphoric acid and maleic acid.

I claim:

1. A dyestuif composition comprising a salt of an acid polybasic acid ester of a leuco compound of avat dyestuif, and-caffeine.

2. A dyestuff composition comprising a salt of an acid sulfuric acid ester of a leuco compound of a vat dyestuff, and a xanthinic base.

3. A dyestuff composition comprising an alkali metal salt of an acid sulfuric acid ester of a leuco compound of a vat dye'stuff and a Xanthinic base. said salt having a solubility in water at 25 C. not exceeding 5 per cent by weight.

8 "4. A'dyestufi? composition comprising a salt of an acid sulfuric acid ester of a leuco compound of a vat dyestufi, and caffeine in an amount equal to at least one-fourth of the weight of the vat dyestuif equivalent of said salt.

5. A dyestuff composition. comprising a sodium saltof an acid sulfuric acid ester of a leuco com pound of a vatdyestuif and caffeine in an amount equal to one-fourth to 5 times the weight of the vat dyestuff equivalent of said salt, said salt saving a solubility in water at 25 C. not exceeding 5 per cent by weight. 6. A printing paste comprising a salt of an acid sulfuric acid ester of a leuco compound of a vat dyestuff, caffeine, and a thickener.

7. A dyestuff composition comprising an alkali metal salt of anacid sulfuric acid ester of a leuco compound of a vat dyestuff, and caffeine in an amount equal to one-fourth to 5 times the weight of the vat dyestuff equivalent of said salt, said salt having a solubility in water at 25 C. not exceeding 5 per cent by weight. a

8. A dyestuff composition comprising the sodium salt of the acid sulfuric acid ester of the leuco compound of the blue-green vat dyestuff obtained by thionation of Z-nethyl-benzam throne, and caffeine in an amount equal to onefourth to five times the weight of the vat dye'stufl equivalent of said salt.

9. A process for the coloration of textile ma" terials, which comprises applying thereto a salt of an acid polybasic acid ester of a leuco compound of a vat dyestuff together with a Xanthinic base, and developing the dyestuff by oxidation on the material in an acid medium.

10. A process for the coloration of textile ma terials, which comprises applying thereto a salt of an acid sulfuric acid ester of a leuco compound of a vat dyestuff together with caffeine, and developing the dyestuff by oxidation on the material in an acid medium.

11. A proces fo printing textile material,

which comprises applying thereto a printing paste containing a sodium salt of an acid sulfuric acid ester of a leuco compound of a vat dyestufi, a thickener, and caffeine in an amount equal to at least one-fourth of the weight of the vat dyestuff equivalent of said salt, and developing the dyestuff by oxidation on the material in an acid medium.

12. A process for printing textile materials, which comprises applying thereto a printing paste containing the sodium salt of the acid sulfuric acid ester of the blue-green vat dyestufi obtained by thionation of Z-methyl-benzathrone, together with a thickener, and caffeine in an amount equal to one-fourth to 5 times the'weight of the vat dyestufi equivalent of said ester salt, and developing the dye-stuff by oxidation on the material in an acid medium.

13. A dyestufi composition comprising the sodium salt of the acid sulfuric acid ester of the leuco compound of 6,6-diethoxy-thioindigo, and caffeine.

14. A dyestuff composition comprising the sodium salt of the acid sulfuric acid ester of the leuco compound of 3,4,8,9-dibenzopyrene-5,10- quinone, and caffeine.

- EARL W. CLARK.

Certificate of Correction Patent N 0. 2,406,586: August 27, 1946.

EARL W. CLARK It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Column 6, line 71, after of insert a; column 7, line 62, claim 1, strike out cafieine and insert instead a xanthinic base; and line 65, claim 2, strike out a xanthinic base and insert instead cafleinc; column 8, line 11, claim 5, for saving read having; and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 29th day of October, A. D. 1946.

LESLIE FRAZER,

First Assistant Commissioner of Patents. 

